National technical standards exist to define the physical and electrical characteristics of electrical plugs and their associated sockets. The intent of the technical standards is to promote safety and operability between power sources and products that require power. Historically, a particular product would be designed for a specific source voltage and maximum current source and so would be manufactured with a fixed plug that is configured to insert into its complementary power-source socket. For example, a product requiring 110 volts and drawing a maximum of 15 A current would be configured with a National Electrical Manufacturers Association (NEMA) 5-15 plug for insertion into a NEMA 5-20 socket. A NEMA 5-15 plug is configured per its NEMA technical standard so that it cannot be inserted into a higher-power NEMA 6-20 socket. More recently, however, products are manufactured having built-in power electronics that are capable of converting various input power into an appropriate power for the device. While a device might be configured with a NEMA 5-15 plug, it may be operable with power provided by a NEMA 6-20 socket, even though not physically able to be inserted into the NEMA 6-20 without an adapter of some sort.
Unfortunately, not every product has build-in power electronics that are capable of adapting to various source voltages. A user that purchases an off-the-shelf electrical plug adapter to make use of a socket defined by a first technical standard for their product having a plug defined by a second technical standard may inadvertently trip safety breakers on the power source or destroy their product (i.e., the “load”) because of an incompatible source voltage. A need continues to exist to protect power sources and products from incompatible adapter and electronic product combinations.